| 摘要 |
PURPOSE:To obtain the titled colorless glass excellent in devitrification resistance and chemical durability by making TeO2, GeO2, TlO2, Bi2O3 and PbO of a special composition an essential component. CONSTITUTION:10-48% (shown by weight hereinafter) TeO2, 5-25% GeO2, 10-37% TlO2, 4-28% Bi2O3, 4-25% PbO, 10-50%=BiO2+PbO, 0-6% B2O3, 0-6% one and two or more kinds of R2O (R is Li, Na, K and Cs), 0-5% ZnO and 0-10% Nb2O3 are mixed and the mixture is introduced into a crucible heated preliminarily at 700-900 deg.C, melted, cleared and homogenized and thereafter cast into a metallic mold preheated at the suitable temp. and slowly cooled to obtain the refraction optical glass of 2.0-2.2 refractive index. |
